The present invention relates to a modular housing for a substrate with electronic components, wherein the housing comprises at least a base part and a cover part, wherein the parts of the housing consist of an electrically conductive material for electromagnetic shielding and form outer walls enclosing a space inside the housing which accommodates the substrate, wherein dividing walls extend in the space inside the housing and have free edges which support the substrate.
Electronic components which are mounted on a substrate, generally a printed circuit board, are often enclosed in a housing which consists of an electrically conductive material for electromagnetic shielding. To allow easy assembling and dismantling of the housing, e.g. for service purposes, it consists generally of two or more parts which are fixed to each other by connection means, for example screws.
In some cases, it is necessary to shield different sections of a substrate against each other because interference may disturb the circuits, especially if radio frequency circuits are mounted on the substrate. For this purpose, a housing with dividing walls inside the space for the substrate is described in U.S. Pat. No. 4,661,888. The housing consists of a base plate and two cover plates on opposite sides of the base. Both the base and the covers have dividing walls supporting a substrate which is located between the base and a cover. The free edges of the dividing walls contact continuous grounding strip conductors on the substrate. In this way, different sections of the substrate are shielded against each other. The contact between the walls and the conducting strips is improved by conductive elastomer gaskets which are disposed on the edges of the walls.
In the design described above, the connecting means press the parts of the housing onto the opposing sides of the substrate, i. e. the substrate separates the parts from each other. Consequently, the mechanical stability of the housing is limited by the properties of the substrate. In most cases, the thermal expansion coefficients of the housing and the substrate differ. This causes mechanical stress which may lead to damage of the electronic circuits on the substrate when the housing is subject to temperature changes resulting from external influences or heat generation from components inside. Mechanical stress can also be caused by tolerances in the dimensions of the parts or improper fixing of the parts to each other. Finally, in the state of the art the cooling of the components in the housing is achieved by air circulation through holes in the outer walls which impair the shielding. However, thermal air circulation is not possible for space applications. Consequently, other means for heat dissipation have to be developed.